The present invention relates to a vehicle loading and unloading system, and more particularly to a system including an automated forklift carriage used for loading and unloading articles into and from transport trucks.
U.S. Pat. No. 4,439,093 issued in 1984 to R. W. Victorino discloses a system for handling palletized articles. This system includes inter alia the step of loading the palletized articles into a conventional semi-trailer truck with a conventional forklift truck, as known in the art. However, it becomes difficult to efficiently load a semi-trailer truck with palletized articles, without unnecessarily losing space inside the truck, and at an efficient speed, without the forklift truck driver accidentally hitting the semi-trailer truck walls with the articles while loading them, considering the often small lateral clearance between the forklift truck loaded with articles and the semi-trailer lateral walls.
Some automated truck loading systems have been developed, such as the one shown in U.S. Pat. No. 4,171,178 issued in 1979 to R. Birkenfeld et al. In this patent, a rail-guided carriage is shown to be used to load a truck from its lateral sides. The rail-guided carriage has the disadvantage of requiring a flawless alignment of the truck relative to the loading dock for loading the articles into the truck in a space-efficient manner. Indeed, should the truck be positioned in a non-parallel relationship with the carriage rails, then the articles will be positioned in a non-parallel fashion relative to the truck walls, and economically valuable space will be wasted inside the semi-trailer. Also, the Birkenfeld patent shows a truck being loaded sidewardly, but it is understood that it is more complex and it requires more precision for a carriage to be aligned relative to the rear opening of a conventional rearwardly-opened semi-trailer truck such as the one shown in the above-mentioned Victorino patent, than it is for a carriage to be aligned with the often wider side openings of laterally loaded trucks such as the one shown in the Birkenfeld patent. Also, conventional merchandise semi-trailers are more often provided with a rear opening, so the Birkenfeld system is not representative of the most likely type of truck encountered.
It is thus an object of the present invention to circumvent the disadvantages of the prior art systems and apparatuses, by providing a truck loading system which allows a conventional truck to be loaded with articles which will be automatically aligned relative to the truck opening.
It is another object of the present invention to provide an article-carrying carriage which will self-align itself between fixed spaced-apart surfaces.
The present invention relates to a carriage for carrying articles, said carriage having two sides, and a front and a rear end defining a longitudinal axis therebetween, said carriage comprising a main rigid frame, ground-engaging wheels rollably mounted to said frame parallel to said longitudinal axis for carrying said frame over ground, a motor mounted to said frame for feeding power to and driving said carriage along said longitudinal axis, a powered article-carrying device mounted to said carriage frame for carrying the articles on said carriage, and a number of lateral idle guide wheels horizontally rollably mounted to said frame and laterally protruding beyond said frame on both said carriage sides for rollable abutment of said alignment wheels against lateral surfaces for allowing self-alignment of said carriage with respect to the lateral surfaces when said carriage is moving along said longitudinal axis.
Preferably, the carriage further comprises a linkage pivotally attached to said frame and rollably carrying said idle guide wheels, said guide wheels forced by said linkage into an integral common displacement relative to said frame so as to remain symmetrically disposed relative to said frame at all times, said guide wheels carried by said linkage being movable between an inner limit position toward said frame and an outer limit position away from said frame, said carriage also comprising a spring member mounted to said frame and continuously biasing said wheels through the instrumentality of said linkage towards said outer limit position; and wherein said carriage is adapted for self-alignment between spaced-apart surfaces by means of said guide wheels continuously rollably engaging the spaced-apart surfaces and by means of said linkage and said spring member forcing said guide wheels to remain symmetrically disposed relative to said carriage frame.
Preferably, said carriage further comprises a control unit for automatically controlling the displacement of said carriage along said longitudinal axis.
Preferably, said spring member is a hydraulic cylinder.
Preferably, said article-carrying member is a powered hydraulic forklift member located at said carriage front end.
The present invention also relates to a vehicle loading and unloading system for loading articles into and unloading articles from a number of vehicles each located at a respective loading station and each including a storage area having an open end and inner side walls, said system including:
a carriage for carrying articles, said carriage having two sides, and a front and a rear end defining a longitudinal axis therebetween, said carriage comprising a main rigid frame, ground-engaging wheels rollably mounted to said frame parallel to said longitudinal axis for carrying said frame over ground, a motor for feeding power to and driving said carriage along said longitudinal axis, a powered article-carrying device mounted to said frame for carrying the articles on said carriage, and a number of lateral idle guide wheels horizontally rollably mounted to said frame and laterally protruding beyond said frame on both said carriage sides for rollable abutment of said guide wheels against the vehicle storage area side walls for allowing self-alignment of said carriage with respect to the vehicle storage area side walls when said carriage is moving along said longitudinal axis; and
a bogie, able to carry said carriage and movable along a bogie horizontal axis transverse to said carriage longitudinal axis, said bogie comprising a motor for feeding power to and moving said bogie along said bogie axis, and a platform for receiving and supporting said carriage thereon and defining two sides and a front and a rear end portions, said bogie front end portion being opened at least when said carriage rolls out of and back onto said bogie; wherein said bogie is movable between the loading stations to allow said carriage to load articles onto and unload articles from the different vehicles storage areas located at each one of the loading stations.
Preferably, said carriage further comprises a linkage pivotally attached to said frame and rollably carrying said idle guide wheels, said guide wheels forced by said linkage into an integral common displacement relative to said frame so as to remain symmetrically disposed relative to said frame at all times, said guide wheels carried by said linkage being movable between an inner limit position toward said frame and an outer limit position away from said frame, said carriage further comprising a spring member mounted to said frame and continuously biasing said wheels through the instrumentality of said linkage towards said outer limit position; and wherein said carriage is adapted for self-alignment and self-centering between the vehicle storage area side walls by means of said guide wheels rollably engaging the side walls and by means of said linkage and said spring member forcing said guide wheels to remain symmetrically disposed relative to said carriage frame.
Preferably, said bogie comprises two parallel railings each fixedly attached to a corresponding said side of said bogie, the distance between said railings being equal to or lesser than the width of said carriage when said guide wheels are in said outer limit position, said railings vertically registering with said guide wheels, said guide wheels consequently continuously engaging said railings while said carriage is located between said railings for self-aligning and self-centering said carriage on said bogie due to said spring member and said linkage.
Preferably, said bogie further comprises a pair of gates pivotally mounted on each said side of said bogie at said bogie front end portion, said gates vertically registering with said carriage guide wheels and being pivotable between a closed condition in which they do not extend beyond the bogie front end portion, and an opened condition in which they extend beyond the bogie front end portion in a co-extensive and substantially collinear fashion relative to said railings, said gates having outer free ends destined to engage the two vehicle storage area side walls, for providing continuous side panels formed on either side of said carriage by said railings, said gates and the vehicle side walls, for continuous engagement of the side panels by said carriage guide wheels when said carriage moves between said bogie and said vehicle, said carriage thus being self-aligned and self-centered relative to said vehicle storage area during article loading and unloading operations in said vehicle storage area.
Preferably, said system further comprises a control unit for automatically controlling the displacement of said bogie along said bogie axis, the displacement of said carriage along said longitudinal axis, and the pivotal displacement of said gates.
Preferably, said spring member is a hydraulic cylinder.
Preferably, said article-carrying member is a powered hydraulic forklift member located at said carriage front end.
Preferably, said system further comprises a conveyor for conveying articles and located frontwardly of said bogie, wherein said carriage is destined to carry the articles with said forklift member from said conveyor into the vehicle for unloading them therein.
Preferably, said conveyor is an overhead conveyor located spacedly above ground, said carriage carrying the articles being destined to move underneath said overhead conveyor and to reach the articles on the conveyor with said forklift member.
Preferably, said control unit further automatically controls said conveyor, for positioning the articles thereon in a precise centered relationship relative to said bogie.
Preferably, said bogie is movable on fixed rails.
The present invention further relates to a vehicle loading and unloading system for loading articles into and unloading articles from a number of vehicles each located at a respective loading station and each having a storage area including an open end and parallel inner side walls, said system including:
a loading dock at each said loading station, adapted to receive in a closely adjacent fashion the open end of the vehicle;
a bridge panel at each said loading station, for bridging each said loading dock with a corresponding vehicle storage area;
a carriage for carrying articles, said carriage having two sides, and a front and a rear end defining a longitudinal axis therebetween, said carriage comprising:
a main rigid frame;
ground-engaging wheels rollably mounted to said frame parallel to said longitudinal axis for carrying said frame over ground;
a motor for feeding power to and driving said carriage along said longitudinal axis;
a powered forklift member mounted to said frame at said front end thereof for carrying the articles on said carriage;
a linkage pivotally attached to said frame;
a number of lateral idle guide wheels horizontally rollably mounted to said linkage and laterally protruding beyond said frame on both said carriage sides, said guide wheels forced by said linkage into an integral common displacement relative to said frame so as to remain symmetrically disposed relative to said frame at all times, said guide wheels carried by said linkage being movable between an inner limit position toward said frame and an outer limit position away from said frame; and
a spring member mounted to said frame and continuously biasing said wheels through the instrumentality of said linkage towards said outer limit position;
said system further comprising:
a bogie mounted to fixed rails, able to carry said carriage and movable along a bogie horizontal axis transverse to said carriage longitudinal axis, said bogie comprising:
a motor for feeding power to and moving said bogie along said bogie axis;
a platform for receiving and supporting said carriage thereon and defining two sides and a front and a rear end portions;
two parallel railings each fixedly attached to a corresponding said side of said bogie, the distance between said railings being equal to or lesser than the width of said carriage when said guide wheels are in said outer limit position, said railings vertically registering with said guide wheels; and
a pair of gates pivotally mounted on each said side of said bogie at said bogie front end portion and defining outer free ends, said gates vertically registering with said guide wheels and being pivotable between a closed condition in which they do not extend beyond the bogie front end portion, and an opened condition in which they extend beyond the bogie front end portion in a co-extensive and substantially collinear fashion relative to said railings, and in which they clear the bogie front end portion;
and said system further comprising a conveyor, for conveying articles to be loaded into vehicles to each said loading station and for conveying articles unloaded from vehicles from each said loading station;
wherein said bogie is movable between the loading stations to allow said carriage to load articles onto or unload articles from vehicles located at each one of the loading stations, with said gates opening at each station where loading or unloading operations are to take place, said gates destined to abut with their outer free end portions against the side walls of the vehicle for forming with said railings and the vehicle side walls continuous side panels which will be continuously engaged by said carriage guide wheels while said carriage moves between said bogie and said vehicle storage area, thereby allowing self-alignment and self-centering of said carriage into said vehicle storage area due to the bias of said spring member against said guide wheels through the instrumentality of said linkage.